While scientists are achieving important gains in the improved treatment of diabetes, preventing the disease is a top priority in the diabetes research community. By learning more about why certain people are at high risk for developing diabetes, scientists may be able to develop ways to stop the disease before it starts, or at least delay its development.
Researchers do not yet fully understand why American Indians, and especially the Pima Indians, are more likely to develop diabetes, but one thing is clear-those who are overweight are at high risk. Approximately 80 percent of people with diabetes are overweight.
Studies have shown that American Indians, Africans and Hispanics living in their native homelands- where the traditional diet is low in fat and daily activities involve walking, gardening, farming, and other forms of physical labor-have very low rates of unhealthy weight and diabetes.
When these groups adopt the high fat diet and inactive lifestyle typical of Western civilization, weight gain, and frequently, diabetes and its complications become significant health problems. Researchers think that if these minority populations returned to their native diet and lifestyle, the risk of diabetes could be reduced and people who already have the disease might be healthier.
To test these and other theories on prevention, NIH has launched a nationwide, multi-center clinical study, the Diabetes Prevention Program, to see if diabetes can be prevented or delayed in people at high risk for developing the disease. The NIH is recruiting several hundred Native Americans at high risk for developing diabetes to participate in the six-year study. Volunteers will be selected from among several American tribes, including the Pima Indians. Dr. William Knowler, chief of the Diabetes and Epidemiology Section at NIDDK, and Dr. Venkat Narayan, an NIDDK visiting scientist, will direct the study in the Pima Indians.
To prepare for this multi-center study, NIH researchers conducted a pilot study with 95 Pima Indians who are diabetes-free and have normal glucose tolerance tests. Researchers wanted to determine if study participants would follow a diet and exercise program, and participate in a cultural education program about their native heritage to learn more about the healthy lifestyle of their ancestors.
"We wanted to find out how best to work with people to bring about lifestyle changes," says Dr. Narayan, co-director of the pilot study.
The two groups in the pilot study were called Pima Action and Pima Pride. Volunteers in the Pima Action group were encouraged to eat a lower-fat, higher-fiber diet. The staff encouraged study participants to increase their consumption of foods such as beans, fruits and vegetables, and suggested recipes that can be prepared at home. The educational program included discussing healthy traditional behaviors that involved nutrition and exercise.
Volunteers in the Pima Action group were also encouraged to exercise three hours a week. Individuals were expected to expend additional calories exercising in leisure and occupational activities they enjoyed, recording their activities in a journal. Program staff met with study volunteers at 3, 6 and twelve month intervals to measure their progress. To maintain motivation and morale, volunteers exercised or worked in groups when possible, and were followed by local trained staff.
While Pima Action focused on weight loss, Pima Pride was an educational program that encouraged study volunteers to discover how their ancestors' values and lifestyle are relevant to their lives. Participants in Pima Pride attended presentations by community members and others to learn more about their ancestors' healthy diets and lifestyles.
Results from the pilot study have been promising, says Dr. Narayan. "What we've seen so far indicates that study participants are eager to try to make healthy lifestyle changes. Individuals have been willing to participate in the study and follow the goals. We're encouraged that the larger study will be successful."
After completing analysis of the data from the pilot study, the researchers will make adjustments to the diet/exercise and cultural education programs. They are developing an intervention that may combine other treatments with the best aspects of the Pima Pride and Pima Action programs. Recruitment for the study should begin in 1996.
- Lorraine H. Marchand